1. Field of the Invention
The invention generally relates to apparatus for venting heated air from a building to reduce heat loading within the building. In particular, the invention relates to venting of heated air from the upper portions of a room to cool the room.
2. Description of the Prior Art
The prior art has previously recognized problems associated with inadequate ventilation of a building. Such problems are particularly acute during the summer months when excessively hot air accumulates in attics and the like, thereby producing a heat loading within the building which penetrates into living areas to render such areas uncomfortable at best. The use of mechanical refrigeration devices for relieving heat loading in living areas is rendered more costly when attic volumes are not ventilated or are inadequately ventilated. Prior attempts to address these problems have invariably involved venting of heated air from an attic or upper portion of a building (which attic or upper portion typically is not used for habitation). To this end, attic ventilation fans have been commonly provided in the roof of a building, the fan exhausting heated air from the attic on build-up of sufficiently undesirable thermal conditions within the interior of the attic. Natural ventilation systems have also been employed, such systems not requiring power as do attic fans. The natural ventilation systems operate passively by creating natural air flow paths through an attic or upper portion of a building immediately below the roof of the building. However, even with active or passive ventilation systems, substantial heat builds up within an attic of a building to transmit uncomfortable heat loads into environmental spaces of the building. Insulation provided between the attic and a room beneath the attic, while effective in winter, actually serves to aggravate the summer thermal problem since heat from the "radiant heat trap" which an attic becomes in summer penetrates the insulation during the day. This heat must be removed from the insulation by natural or mechanical cooling before the heat loading in the rooms beneath the attic can begin to cool to a comfortable temperature. While insulation assists in conserving heat during the winter, the present invention teaches that insulation (and the more insulation, the worse is the problem) actually causes the time period required to dissipate or mechanically remove a given heat loading from a building to be increased. On an annual basis, insulation may make little difference in total energy cost when mechanical refrigeration is used to cool a building. The present invention therefore is intended to provide a method and apparatus which can be used solely or in combination with existing active and/or passive ventilation systems to reduce the heat loading within a building during "warm" weather and to thereby conserve energy normally required to mechanically cool the building to a comfortable living temperature.